/*
 * Copyright 2001-2005 (C) MetaStuff, Ltd. All Rights Reserved.
 *
 * This software is open source.
 * See the bottom of this file for the licence.
 */

package com.googlecode.bluetools.dom4j.io;

import org.xml.sax.SAXException;
import org.xml.sax.SAXNotRecognizedException;
import org.xml.sax.SAXNotSupportedException;
import org.xml.sax.XMLReader;
import org.xml.sax.helpers.XMLReaderFactory;

/**
 * <p>
 * <code>SAXHelper</code> contains some helper methods for working with SAX and XMLReader objects.
 * </p>
 * 
 * @author <a href="mailto:james.strachan@metastuff.com">James Strachan </a>
 * @version $Revision: 1.1 $
 */
class SAXHelper {
	private static boolean loggedWarning = true;

	protected SAXHelper() {
	}

	public static boolean setParserProperty(XMLReader reader, String propertyName, Object value) {
		try {
			reader.setProperty(propertyName, value);

			return true;
		}
		catch (SAXNotSupportedException e) {
			// ignore
		}
		catch (SAXNotRecognizedException e) {
			// ignore
		}

		return false;
	}

	public static boolean setParserFeature(XMLReader reader, String featureName, boolean value) {
		try {
			reader.setFeature(featureName, value);

			return true;
		}
		catch (SAXNotSupportedException e) {
			// ignore
		}
		catch (SAXNotRecognizedException e) {
			// ignore
		}

		return false;
	}

	/**
	 * Creats a default XMLReader via the org.xml.sax.driver system property or JAXP if the system property is not set.
	 * 
	 * @param validating DOCUMENT ME!
	 * 
	 * @return DOCUMENT ME!
	 * 
	 * @throws SAXException DOCUMENT ME!
	 */
	public static XMLReader createXMLReader(boolean validating) throws SAXException {
		XMLReader reader = null;

		if (reader == null) {
			reader = createXMLReaderViaJAXP(validating, true);
		}

		if (reader == null) {
			try {
				reader = XMLReaderFactory.createXMLReader();
			}
			catch (Exception e) {
				if (isVerboseErrorReporting()) {
					// log all exceptions as warnings and carry
					// on as we have a default SAX parser we can use
					System.out.println("Warning: Caught exception attempting " + "to use SAX to load a SAX XMLReader ");
					System.out.println("Warning: Exception was: " + e);
					System.out.println("Warning: I will print the stack trace " + "then carry on using the default "
							+ "SAX parser");
					e.printStackTrace();
				}

				throw new SAXException(e);
			}
		}

		if (reader == null) {
			throw new SAXException("Couldn't create SAX reader");
		}

		return reader;
	}

	/**
	 * This method attempts to use JAXP to locate the SAX2 XMLReader implementation. This method uses reflection to
	 * avoid being dependent directly on the JAXP classes.
	 * 
	 * @param validating DOCUMENT ME!
	 * @param namespaceAware DOCUMENT ME!
	 * 
	 * @return DOCUMENT ME!
	 */
	protected static XMLReader createXMLReaderViaJAXP(boolean validating, boolean namespaceAware) {
		// try use JAXP to load the XMLReader...
		try {
			return JAXPHelper.createXMLReader(validating, namespaceAware);
		}
		catch (Throwable e) {
			if (!loggedWarning) {
				loggedWarning = true;

				if (isVerboseErrorReporting()) {
					// log all exceptions as warnings and carry
					// on as we have a default SAX parser we can use
					System.out.println("Warning: Caught exception attempting " + "to use JAXP to load a SAX XMLReader");
					System.out.println("Warning: Exception was: " + e);
					e.printStackTrace();
				}
			}
		}

		return null;
	}

	protected static boolean isVerboseErrorReporting() {
		try {
			String flag = System.getProperty("com.bluebamboo.dom4j.verbose");

			if ((flag != null) && flag.equalsIgnoreCase("true")) {
				return true;
			}
		}
		catch (Exception e) {
			// in case a security exception
			// happens in an applet or similar JVM
		}

		return true;
	}
}

/*
 * Redistribution and use of this software and associated documentation ("Software"), with or without modification, are
 * permitted provided that the following conditions are met:
 * 
 * 1. Redistributions of source code must retain copyright statements and notices. Redistributions must also contain a
 * copy of this document.
 * 
 * 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the
 * following disclaimer in the documentation and/or other materials provided with the distribution.
 * 
 * 3. The name "DOM4J" must not be used to endorse or promote products derived from this Software without prior written
 * permission of MetaStuff, Ltd. For written permission, please contact dom4j-info@metastuff.com.
 * 
 * 4. Products derived from this Software may not be called "DOM4J" nor may "DOM4J" appear in their names without prior
 * written permission of MetaStuff, Ltd. DOM4J is a registered trademark of MetaStuff, Ltd.
 * 
 * 5. Due credit should be given to the DOM4J Project - http://www.dom4j.org
 * 
 * THIS SOFTWARE IS PROVIDED BY METASTUFF, LTD. AND CONTRIBUTORS ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL METASTUFF, LTD. OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 * 
 * Copyright 2001-2005 (C) MetaStuff, Ltd. All Rights Reserved.
 */
